API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-139
Table 20.3—Reference Temperature
Carbon Steels—20 joule or 15 ft-lb Transition Temperature for Each ASME Exemption Curve
Minimum Yield Strength
(ksi)
ASME Exemption (°F)
Curve A Curve B Curve C Curve D
30 104 66 28 2
32 97 59 21 −5
34 91 53 15 −11
36 86 48 10 −16
38 81 43 5 −21
40 78 40 2 −24
42 74 36 −2 −28
44 71 33 −5 −31
46 68 30 −8 −34
48 66 28 −10 −36
50 63 25 −13 −39
Low Alloy Steels—27 joule or 20 ft-lb Transition Temperature for Each ASME Exemption Curve
Minimum Yield Strength
(ksi)
ASME Exemption (°F)
Curve A Curve B Curve C Curve D
30 124 86 48 22
32 115 77 39 13
34 107 69 31 5
36 101 63 25 −1
38 96 58 20 −6
40 92 54 16 −10
42 88 50 12 −14
44 85 47 9 −17
46 81 43 5 −21
48 79 41 3 −23
50 76 38 0 −26
52 73 35 −3 −29
54 71 33 −5 −31
56 69 31 −7 −33
58 67 29 −9 −35
60 65 27 −11 −37
62 63 25 −13 −39
64 62 24 −14 −40
66 60 22 −16 −42
68 58 20 −18 −44
70 57 19 −19 −45
72 56 18 −20 −46
74 54 16 −22 −48
76 53 15 −23 −49
78 52 14 −24 −50
80 51 13 −25 −51